Soft Token Security via Secure Element Segmentation
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Solution Overview
Problem
Soft tokens, such as U-Prove tokens, are vulnerable to copying, which compromises their security and authenticity for authentication purposes.
Innovation Solution
A method that generates a soft token cryptographically linked to a secure element, using an ID token as the data source, with a secure element like a chip card or TPM, and establishing cryptographically secured connections for secure authentication and data transmission, ensuring the token's trustworthiness and user ownership.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If soft tokens are used for authentication purposes, then authentication functionality is provided, but security is compromised due to copying vulnerability
Solution Approach 1:
The invention divides the authentication system into two separate components: a secure element (hardware token) that stores the private key and cannot be copied, and a soft token (software application) that provides the user interface and authentication functionality. The private key is cryptographically split between these components, with the secure element holding the secret portion and the soft token holding the public portion. This segmentation prevents copying attacks because the critical secret key material never exists in a copyable form in the soft token alone.
Solution Approach 2:
The invention introduces a secure element as an intermediary component between the user and the authentication system. This secure element acts as a trusted mediator that holds the private key in a non-copyable form and performs cryptographic operations to generate authentication credentials. The soft token communicates with this intermediary to perform authentication, but the critical security function remains isolated in the secure element, preventing direct copying attacks on the authentication mechanism.
2Ease of operation
If private key is stored in soft token for authentication, then authentication capability is enabled, but trustworthiness decreases due to copying risk
Solution Approach 1:
The authentication system is segmented into a soft token component that provides ease of operation through its user interface and communication capabilities, and a secure element component that provides trustworthiness through hardware-based key protection. The private key is split across these segments, with the secret portion isolated in the secure element. This allows the soft token to remain easy to use while the secure element ensures trustworthiness by preventing key extraction and copying.
Solution Approach 2:
The invention replaces the traditional mechanical approach of storing the entire private key in a single location with a cryptographic substitution approach. Instead of mechanically storing the complete key in the soft token, the system uses cryptographic key splitting where the private key is divided into multiple parts distributed across different security zones. This substitution transforms the security model from physical key protection to cryptographic key distribution, enabling both ease of operation and high trustworthiness.
Data Source
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AI summary
The invention relates to a method for generating a soft token, having the following steps: providing a secure element (172), wherein, in a protected storage area (186) of the secure element, a secret key of an asymmetric cryptographic key pair is stored; setting up a first cryptographically secured connection (180) between an electronic apparatus (174) and a service computer system (150); transmitting a request for the generation of the soft token from the electronic apparatus to the service computer system via the first connection; generating a one time password on the basis of the reception of the request by the service computer system; registering the one time password as an identifier of the first connection by the service computer system; transmitting the one time password from the service computer system to the electronic apparatus via the first connection; issuing the one time password via a user interface (194) of the electronic apparatus; setting up a second cryptographically secured connection (182) between a user computer system (100) and the service computer system; entering the one time password into the user computer system; transmitting the entered one time password from the user computer system to the service computer system via the second connection; verification, by means of the service computer system, whether the registered one time password is in agreement with the one time password received via the second connection, and only if this is the case, reading at least one attribute stored in an ID token (106), generating the soft token by marking the at least one attribute and the public key of the first cryptographic key pair, transmitting the soft token via the first connection to the electronic apparatus and/or transmitting the soft token via the second connection to the user computer system.